1. Field of the Invention
The present application relates to a hetero-bipolar transistor and a method for producing the hetero-bipolar transistor.
2. Background Arts
As a communication apparatus becomes operable in higher frequencies, a semiconductor device applicable to such high frequencies has been continuously requested in the field. One promising device is, what is called, a hetero-junction bipolar transistor (hereafter denoted as HBT). Many prior arts have reported an HBT that stacks, on a semi-insulating GaAs substrate, an n-type GaAs collector, a p-type GaAs base, an emitter constituted by an n-type InGaP and an n-type AlGaAs.
Not only an HBT above described but a semiconductor device generates heat because of a current flowing therein. This self-heating of the semiconductor device sometimes causes thermal runaway. In another aspect, when a temperature of the device rises by the self-heating, the performance and the life time of the device inevitably degrade. Means to dissipate heat efficiently outward of the device are continuously requested. The present application provides solutions to improve the thermal characteristics of the semiconductor device.